Trunk muscle activation patterns in subjects with low back pain

Low back pain (LBP) is nowadays one of the most widely experienced health-related problems. First symptoms usually appear between the age of thirty and fifty, although it has been recorded in athletes in early twenties . Etiology of LBP is multifactorial and it is thought that non-specific LBP is associated with lumbar spine instability 4, . It is generally believed that spinal instability (such as in circumstances with no neurological deficit, deformity, or the presence of pain) is associated with reduced capabilities of neuromuscular system to respond to physiological loadings . The spine is a mechanically complex structure which is inherently unstable. Due to the redundancy in the neuromuscular and spinal system, there is a large set of possible muscle activation patterns to meet the stability constraints . However, different muscle activation patterns can significantly affect the magnitude and direction of the intervertebral loadings and, therefore, the spinal and core stability. Muscle activation patterns when either retaining different postures or performing various movements and their relationship with LBP is of much interest for researchers and the clinical practice. Theoretically, the unbalanced activation and coactivation may lead to a mechanical imbalance of the whole body system 4, . However, there is a disagreement among the researchers to what extent the changes in trunk muscles activation level and recruitment patterns contribute to the presence of pain (and later on to its reduction) and the altered core stability . However, research in the area of motor control has made a significant contribution to understanding of the neuromuscular reorganization due to LBP. Core stability and the role of deep trunk muscles